Role of Electrolyte in Overcoming the Challenges of LiNiO2 Cathode in Lithium Batteries

LiNiO2 (LNO) is a high-capacity and model cathode first discovered in the 1980s that fell out of favor due to its intrinsic instabilities. However, research activities toward LNO are once again on the rise as the push for higher-energy-density cells marches on. We demonstrate here that with appropriate modern electrolytes, major performance improvements can be achieved with LNO with no additional modifications. Cells with a localized high concentration electrolyte (LHCE) deliver 92% capacity retention after 200 cycles compared with 56% capacity retention in a baseline carbonate electrolyte, maintain 94% capacity after high-voltage storage compared with 77% capacity, and display a higher onset temperature of thermal runaway of 244 degrees C compared with 188 degrees C. These improvements are attributed to the LHCE's high oxidative stability and its formation of fluorine-rich interphases. Although further characterization of this new class of electrolyte is necessary, this work demonstrates that modern electrol es can be drop-in enablers of high-capacity, long-cycle-life cells.

Automated summary

This study demonstrates that using a localized high concentration electrolyte (LHCE) can significantly improve the performance of LiNiO2 cathode, enhancing cycle life and onset temperature of thermal runaway. The high oxidative stability and formation of fluorine-rich interphases play a key role in these performance improvements.